21165615201 has 8 divisors (see below), whose sum is σ = 28243420000. Its totient is φ = 14099110272.

The previous prime is 21165615199. The next prime is 21165615209. The reversal of 21165615201 is 10251656112.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21165615201 - 2¹ = 21165615199 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21165615209) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2820595 + ... + 2828088.

It is an arithmetic number, because the mean of its divisors is an integer number (3530427500).

Almost surely, 2^21165615201 is an apocalyptic number.

It is an amenable number.

21165615201 is a deficient number, since it is larger than the sum of its proper divisors (7077804799).

21165615201 is a wasteful number, since it uses less digits than its factorization.

21165615201 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5649935.

The product of its (nonzero) digits is 3600, while the sum is 30.

The spelling of 21165615201 in words is "twenty-one billion, one hundred sixty-five million, six hundred fifteen thousand, two hundred one".